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Wang M, Zhao W, Kong S, Chen J, Li Y, Liu M, Wu M, Wang G. Elucidating the Mass Transportation Behavior of Gas Diffusion Layers via a H 2 Limiting Current Test. Materials (Basel) 2023; 16:5670. [PMID: 37629961 PMCID: PMC10456699 DOI: 10.3390/ma16165670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/14/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023]
Abstract
The gas diffusion layer (GDL), as a key component of proton exchange membrane fuel cells (PEMFCs), plays a crucial role in PEMFC's polarization performance, particularly in mass transport properties at high current densities. To elucidate the correlation between GDLs' structure and their mass transport properties, a limiting current test with the H2 molecular probe was established and employed to investigate three representative GDLs with and without the microporous layer (MPL). By varying humidity and back pressure, the mass transport resistance of three GDLs was measured in an operating fuel cell, and an elaborate analysis of H2 transport was conducted. The results showed that the transport resistance (RDM) of GDLs was affected by the thickness and pore size distribution of the macroporous substrate (MPS) and the MPL. In the process of gas transport, the smaller pore size and thicker MPL increase the force of gas on the pore wall, resulting in an increase in transmission resistance. Through further calculation and analysis, the total transport resistance can be divided into pressure-related resistance (RP) and pressure-independent resistance (RNP). RP mainly originates from the transport resistance in both MPLs and the substrate layers of GDLs, exhibiting a linear relationship to the pressure; RNP mainly originates from the transport resistance in the MPLs. 29BC with thick MPL shows the largest RNP, and T060 without MPL shows the RNP = 0. This methodology enables in situ measurements of mass transport resistances for gas diffusion media, which can be easily applied for developing and deploying PEMFCs.
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Affiliation(s)
- Min Wang
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China; (M.W.); (W.Z.); (J.C.); (Y.L.); (M.L.)
| | - Wei Zhao
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China; (M.W.); (W.Z.); (J.C.); (Y.L.); (M.L.)
| | - Shuhan Kong
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China;
| | - Juntao Chen
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China; (M.W.); (W.Z.); (J.C.); (Y.L.); (M.L.)
| | - Yunfei Li
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China; (M.W.); (W.Z.); (J.C.); (Y.L.); (M.L.)
| | - Mengqi Liu
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China; (M.W.); (W.Z.); (J.C.); (Y.L.); (M.L.)
| | - Mingbo Wu
- College of New Energy, China University of Petroleum (East China), Qingdao 266580, China; (M.W.); (W.Z.); (J.C.); (Y.L.); (M.L.)
| | - Guanxiong Wang
- Shenzhen Academy of Aerospace Technology, Shenzhen 518057, China
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Pärnamäe R, Tedesco M, Wu MC, Hou CH, Hamelers HVM, Patel SK, Elimelech M, Biesheuvel PM, Porada S. Origin of Limiting and Over limiting Currents in Bipolar Membranes. Environ Sci Technol 2023. [PMID: 37341475 DOI: 10.1021/acs.est.2c09410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/22/2023]
Abstract
Bipolar membranes (BPMs), a special class of ion exchange membranes with the unique ability to electrochemically induce either water dissociation or recombination, are of growing interest for environmental applications including eliminating chemical dosage for pH adjustment, resource recovery, valorization of brines, and carbon capture. However, ion transport within BPMs, and particularly at its junction, has remained poorly understood. This work aims to theoretically and experimentally investigate ion transport in BPMs under both reverse and forward bias operation modes, taking into account the production or recombination of H+ and OH-, as well as the transport of salt ions (e.g., Na+, Cl-) inside the membrane. We adopt a model based on the Nernst-Planck theory, that requires only three input parameters─membrane thickness, its charge density, and pK of proton adsorption─to predict the concentration profiles of four ions (H+, OH-, Na+, and Cl-) inside the membrane and the resulting current-voltage curve. The model can predict most of the experimental results measured with a commercial BPM, including the observation of limiting and overlimiting currents, which emerge due to particular concentration profiles that develop inside the BPM. This work provides new insights into the physical phenomena in BPMs and helps identify optimal operating conditions for future environmental applications.
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Affiliation(s)
- Ragne Pärnamäe
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
- Environmental Technology, Wageningen University, Wageningen, The Netherlands
| | - Michele Tedesco
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - Min-Chen Wu
- Graduate Institute of Environmental Engineering, National Taiwan University No.1, Sec. 4. Roosevelt Rd., Taipei 10617, Taiwan
| | - Chia-Hung Hou
- Graduate Institute of Environmental Engineering, National Taiwan University No.1, Sec. 4. Roosevelt Rd., Taipei 10617, Taiwan
| | - Hubertus V M Hamelers
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
- Environmental Technology, Wageningen University, Wageningen, The Netherlands
| | - Sohum K Patel
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, United States
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520-8286, United States
| | - P M Biesheuvel
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
| | - Slawomir Porada
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Leeuwarden, The Netherlands
- Department of Process Engineering and Technology of Polymeric and Carbon Materials, Wroclaw University of Science and Technology, Wyb. Wyspianskiego 27, Wroclaw 50-370, Poland
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Vasil’eva VI, Akberova EM, Saud AM, Zabolotsky VI. Current-Voltage Characteristics of Membranes with Different Cation-Exchanger Content in Mineral Salt-Neutral Amino Acid Solutions under Electrodialysis. Membranes (Basel) 2022; 12:1092. [PMID: 36363647 PMCID: PMC9698414 DOI: 10.3390/membranes12111092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/22/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
The features of the electrochemical behavior of experimental heterogeneous ion-exchange membranes with different mass fractions of sulfonated cation-exchange resin (from 45 to 65 wt%) have been studied by voltammetry during electrodialysis. Electromembrane systems with 0.01 M NaCl solution and with a mixed 0.01 M NaCl + 0.05 M phenylalanine (Phe) solution have been investigated. A significant influence of the ion-exchanger content on the parameters of current-voltage curves (CVCs) was established for the first time. Electrodialysis of the sodium chloride solution revealed a decrease in the length of the limiting current plateau and in the resistances of the second and third sections of the CVCs with an increase in the resin content in the membrane. The fact of the specific shape of the CVCs of all studied cation-exchange membrane samples in mixed solutions of the mineral salt and the amino acid was established. A specific feature of current-voltage curves is the presence of two plateaus of the limiting current and two values of the limiting current, respectively. This phenomenon in electromembrane systems with neutral amino acids has not been found before. The value of the first limiting current is determined by cations of the mineral salt, which are the main current carriers in the system. The presence of the second plateau and the corresponding second limiting current is due to the appearance of additional carriers due to the ability of phenylalanine as an organic ampholyte to participate in protolytic reactions. In the cation-exchange electromembrane system with the phenylalanine containing solution, two mechanisms of H+/OH- ion generation through water splitting and acid dissociation are shown. The possibility of the generation of H+/OH- ions at the enriched solution/cation-exchange membrane interface during electrodialysis of amino acid containing solutions is shown for the first time. The results of this study can be used to improve the process of electromembrane demineralization of neutral amino acid solutions by both targeted selection or the creation of new membranes and the selection of effective current operating modes.
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Affiliation(s)
- Vera I. Vasil’eva
- Department of Analytical Chemistry, Chemical Faculty, Voronezh State University, Universitetskaya pl. 1, 394018 Voronezh, Russia
| | - Elmara M. Akberova
- Department of Analytical Chemistry, Chemical Faculty, Voronezh State University, Universitetskaya pl. 1, 394018 Voronezh, Russia
| | - Ali M. Saud
- Faculty of Science, Tishreen University, Latakia 2237, Syria
| | - Victor I. Zabolotsky
- Department of Physical Chemistry, Faculty of Chemistry and High Technologies, Kuban State University, ul. Stavropolskaya 149, 350040 Krasnodar, Russia
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Rodrigues M, Sleutels T, Kuntke P, Buisman CJN, Hamelers HVM. Effects of Current on the Membrane and Boundary Layer Selectivity in Electrochemical Systems Designed for Nutrient Recovery. ACS Sustain Chem Eng 2022; 10:9411-9418. [PMID: 35910292 PMCID: PMC9326972 DOI: 10.1021/acssuschemeng.2c01764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/01/2022] [Indexed: 06/15/2023]
Abstract
During electrochemical nutrient recovery, current and ion exchange membranes (IEM) are used to extract an ionic species of interest (e.g., ion) from a mixture of multiple ions. The species of interest (ion 1) has an opposing charge to the IEM. When ion 1 is extracted from the solution, the species fractions at the membrane and the adjunct boundary layers are affected. Hence, the species transport through the electrochemical system (ES) can no longer be described as electrodialysis-like. A dynamic state is observed in the compartments, where the ionic species are recovered. When the boundary layer-membrane interface is depleted, the IEM is at maximum current. If the ES is operated at a current higher than the maximum current, the fluxes of both ion 1 and other competing ions, with the same charge (ion 2), occur. This means, for example, ion 1 will be recovered, and the concentration of ion 2 will build up in time. Therefore, a steady state is never reached. Ideally, to prevent the effect of limiting current at the boundary layer-membrane interface, ES for nutrient recovery should be operated at low currents.
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Affiliation(s)
- Mariana Rodrigues
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9,
8911MA Leeuwarden; P.O. Box 1113, 8900CC Leeuwardem, The Netherlands
- Environmental
Technology, Wageningen University, Bornse Weilanden 9, 6708 Wageningen; P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Tom Sleutels
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9,
8911MA Leeuwarden; P.O. Box 1113, 8900CC Leeuwardem, The Netherlands
| | - Philipp Kuntke
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9,
8911MA Leeuwarden; P.O. Box 1113, 8900CC Leeuwardem, The Netherlands
- Environmental
Technology, Wageningen University, Bornse Weilanden 9, 6708 Wageningen; P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Cees J. N. Buisman
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9,
8911MA Leeuwarden; P.O. Box 1113, 8900CC Leeuwardem, The Netherlands
- Environmental
Technology, Wageningen University, Bornse Weilanden 9, 6708 Wageningen; P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Hubertus V. M. Hamelers
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9,
8911MA Leeuwarden; P.O. Box 1113, 8900CC Leeuwardem, The Netherlands
- Environmental
Technology, Wageningen University, Bornse Weilanden 9, 6708 Wageningen; P.O. Box 17, 6700 AA Wageningen, The Netherlands
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5
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Tang K, Zheng H, Du P, Zhou K. Simultaneous Fractionation, Desalination, and Dye Removal of Dye/Salt Mixtures by Carbon Cloth-Modified Flow-electrode Capacitive Deionization. Environ Sci Technol 2022; 56:8885-8896. [PMID: 35658453 DOI: 10.1021/acs.est.2c00982] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The critical challenges of using electromembrane processes [e.g., electrodialysis and flow-electrode capacitive deionization (FCDI)] to recycle resources (e.g., water, salts, and organic compounds) from wastewater are the fractionation of dissolved ionic matter, the removal/recovery of organic components during desalination, and membrane antifouling. This study realized the simultaneous fractionation, desalination, and dye removal/recovery (FDR) treatment of dye/salt mixtures through a simple but effective approach, that is, using a carbon cloth-modified FCDI (CC-FCDI) unit, in which the carbon cloth layer was attached to the surface of each ion-exchange membrane (IEM). The IEMs and carbon-based flow-electrodes were responsible for the fractionation and desalination of dye and salt ions, while the carbon cloth layers contributed to the active membrane antifouling and dye removal/recovery by the electrosorption mechanism. Attributed to such features, the CC-FCDI unit accomplished the effective FDR treatment of dye/salt mixtures with wide ranges of salt and dye concentrations (5-20 g L-1 NaCl and 200-800 ppm methylene blue) and different dye components (cationic and anionic dyes) under various applied voltages (1.2-3.2 V). Moreover, the active membrane antifouling by virtue of the carbon cloth facilitated the excellent and sustainable FDR performance of CC-FCDI. The removal/recovery of dyes from the carbon cloth strongly depends on the characteristics of dye molecules, the surface properties of the carbon cloth, and the local pH at the IEM/CC interfaces. This study sheds light on the strategies of using multifunctional layer-modified FCDI units to reclaim resources from various high-salinity organic wastewater.
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Affiliation(s)
- Kexin Tang
- Environmental Process Modelling Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
| | - Han Zheng
- Environmental Process Modelling Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
- Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Penghui Du
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kun Zhou
- Environmental Process Modelling Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141, Singapore
- Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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6
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Stolz L, Hochstädt S, Röser S, Hansen MR, Winter M, Kasnatscheew J. Single-Ion versus Dual-Ion Conducting Electrolytes: The Relevance of Concentration Polarization in Solid-State Batteries. ACS Appl Mater Interfaces 2022; 14:11559-11566. [PMID: 35192769 PMCID: PMC8915161 DOI: 10.1021/acsami.2c00084] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 02/10/2022] [Indexed: 05/19/2023]
Abstract
Lithium batteries with solid polymer electrolytes (SPEs) and mobile ions are prone to mass transport limitations, that is, concentration polarization, creating a concentration gradient with Li+-ion (and counter-anion) depletion toward the respective electrode, as can be electrochemically observed in, for example, symmetric Li||Li cells and confirmed by Sand and diffusion equations. The effect of immobile anions is systematically investigated in this work. Therefore, network-based SPEs are synthesized with either mobile (dual-ion conduction) or immobile anions (single-ion conduction) and proved via solvation tests and nuclear magnetic resonance spectroscopy. It is shown that the SPE with immobile anions does not suffer from concentration polarization, thus disagreeing with Sand and diffusion assumptions, consequently suggesting single-ion (Li+) transport via migration instead. Nevertheless, the practical relevance of single-ion conduction can be debated. Under practical conditions, that is, below the limiting current, the concentration polarization is generally not pronounced with DIC-based electrolytes, rendering the beneficial effect of SIC redundant and DIC a better choice due to better kinetical aspects under these conditions. Also, the observed dendritic Li in both electrolytes questions a relevant impact of mass transport on its formation, at least in SPEs.
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Affiliation(s)
- Lukas Stolz
- Helmholtz-Institute
Münster, IEK-12, Forschungszentrum
Jülich GmbH, Corrensstraße
46, 48149 Münster, Germany
| | - Sebastian Hochstädt
- Institute
of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Stephan Röser
- Helmholtz-Institute
Münster, IEK-12, Forschungszentrum
Jülich GmbH, Corrensstraße
46, 48149 Münster, Germany
- E-Lyte
Innovations GmbH, Mendelstraße
11, 48149 Münster, Germany
| | - Michael Ryan Hansen
- Institute
of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Martin Winter
- Helmholtz-Institute
Münster, IEK-12, Forschungszentrum
Jülich GmbH, Corrensstraße
46, 48149 Münster, Germany
- MEET
Battery Research Center, Institute of Physical Chemistry, University of Münster, Corrensstraße 46, 48149 Münster, Germany
| | - Johannes Kasnatscheew
- Helmholtz-Institute
Münster, IEK-12, Forschungszentrum
Jülich GmbH, Corrensstraße
46, 48149 Münster, Germany
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Chowdhury A, Bird A, Liu J, Zenyuk IV, Kusoglu A, Radke CJ, Weber AZ. Linking Perfluorosulfonic Acid Ionomer Chemistry and High-Current Density Performance in Fuel-Cell Electrodes. ACS Appl Mater Interfaces 2021; 13:42579-42589. [PMID: 34490780 DOI: 10.1021/acsami.1c07611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Transport phenomena are key in controlling the performance of electrochemical energy-conversion technologies and can be highly complex, involving multiple length scales and materials/phases. Material designs optimized for one reactant species transport however may inhibit other transport processes. We explore such trade-offs in the context of polymer-electrolyte fuel-cell electrodes, where ionomer thin films provide the necessary proton conductivity but retard oxygen transport to the Pt reaction site and cause interfacial resistance due to sulfonate/Pt interactions. We examine the electrode overall gas-transport resistance and its components as a function of ionomer content and chemistry. Low-equivalent-weight ionomers allow better dissolved-gas and proton transport due to greater water uptake and low crystallinity but also cause significant interfacial resistance due to the high density of sulfonic acid groups. These effects of equivalent weight are also observed via in situ ionic conductivity and CO displacement measurements. Of critical importance, the results are supported by ex situ ellipsometry and X-ray scattering of model thin-film systems, thereby providing direct linkages and applicability of model studies to probe complex heterogeneous structures. Structural and resultant performance changes in the electrode are shown to occur above a threshold sulfonic-group loading, highlighting the significance of ink-based interactions. Our findings and methodologies are applicable to a variety of solid-state energy-conversion devices and material designs.
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Affiliation(s)
- Anamika Chowdhury
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Ashley Bird
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Jiangjin Liu
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Iryna V Zenyuk
- Department of Chemical and Biomolecular Engineering, University of California Irvine, Irvine, California 92697, United States
| | - Ahmet Kusoglu
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Clayton J Radke
- Department of Chemical and Biomolecular Engineering, University of California Berkeley, Berkeley, California 94720, United States
| | - Adam Z Weber
- Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Gurieff N, Keogh DF, Timchenko V, Menictas C. Enhanced Reactant Distribution in Redox Flow Cells. Molecules 2019; 24:E3877. [PMID: 31661797 DOI: 10.3390/molecules24213877] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 11/16/2022] Open
Abstract
Redox flow batteries (RFBs), provide a safe and cost-effective means of storing energy at grid-scale, and will play an important role in the decarbonization of global electricity networks. Several approaches have been explored to improve their efficiency and power density, and recently, cell geometry modification has shown promise in efforts to address mass transport limitations which affect electrochemical and overall system performance. Flow-by electrode configurations have demonstrated significant power density improvements in laboratory testing, however, flow-through designs with conductive felt remain the standard at commercial scale. Concentration gradients exist within these cells, limiting their performance. A new concept of redistributing reactants within the flow frame is introduced in this paper. This research shows a 60% improvement in minimum V3+ concentration within simulated vanadium redox flow battery (VRB/VRFB) cells through the application of static mixers. The enhanced reactant distribution showed a cell voltage improvement by reducing concentration overpotential, suggesting a pathway forward to increase limiting current density and cycle efficiencies in RFBs.
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Gourdin G, Xiao N, McCulloch W, Wu Y. Use of Polarization Curves and Impedance Analyses to Optimize the "Triple-Phase Boundary" in K-O 2 Batteries. ACS Appl Mater Interfaces 2019; 11:2925-2934. [PMID: 30596423 DOI: 10.1021/acsami.8b16321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
K-O2 superoxide batteries have shown great potential for energy-storage applications due to the unique single-electron redox processes in the oxygen or gas-diffusion electrode. Optimization of the 'triple-phase boundary', the region of the cathode where the O2, electrolyte, and electrode surface are in immediate contact, is crucial for maximizing their power performance, but one that has not been explored. Herein, we demonstrate an efficient method for maximizing the power capabilities of the K-O2 battery system by optimizing the interface using polarization and impedance analyses. At the one extreme, an electrolyte volume-deficient state decreases access to the electrochemically active surface area resulting in a limitation of the maximum power output of the K-O2 battery, whereas an excess electrolyte volume state increases the diffusion path to the active surface area for the dissolved O2 inducing mass-transfer limitations sooner, which results in a decrease in the current and power output. Finally, we show that the optimal electrolyte volume closely matches the void volume of the internal cell materials (separators, cathode) resulting in a maximization of the electrochemically accessible surface area while minimizing the O2 diffusion path.
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Affiliation(s)
- Gerald Gourdin
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - Neng Xiao
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - William McCulloch
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
| | - Yiying Wu
- Department of Chemistry and Biochemistry , The Ohio State University , 100 West 18th Avenue , Columbus , Ohio 43210 , United States
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10
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Nebavskaya X, Sarapulova V, Butylskii D, Larchet C, Pismenskaya N. Electrochemical Properties of Homogeneous and Heterogeneous Anion Exchange Membranes Coated with Cation Exchange Polyelectrolyte. Membranes (Basel) 2019; 9:E13. [PMID: 30641931 DOI: 10.3390/membranes9010013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/29/2018] [Accepted: 01/06/2019] [Indexed: 11/28/2022]
Abstract
Coating ion exchange membranes with polyelectrolyte has been proven to be a cheap way to reduce concentration polarization and increase limiting current (for polyelectrolytes carrying fixed groups of the same sign of charge with respect to the membrane bulk), to create high monovalent selectivity, and to add the function of H+/OH− ions generation (for polyelectrolytes bearing fixed groups of the opposite sign of charge with respect to the membrane bulk). In the latter case, the balance between the counterion transport and the H+/OH− ions generation is affected by parameters of the substrate and the modifying layer. In this study we investigated the electrochemical characteristics of homogeneous Neosepta AMX-Sb and heterogeneous MA-41P membranes coated with one, two, or three layers of oppositely charged polyelectrolyte (the maximum thickness of each layer was 5 µm). It was found that the limiting current decreased earlier and the generation of H+/OH− ions was stronger in the case of the heterogeneous membrane. The shift in the pH of the solution depended more on the generation of H+/OH− ions at the modifying layer/solution interface than on the generation at the membrane/modifying layer interface, and in all cases water splitting started in the same range of potential drops over the membrane.
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Abstract
When integrated into microfluidic chips, ion-selective nanoporous polymer and solid-state membranes can be used for on-chip pumping, pH actuation, analyte concentration, molecular separation, reactive mixing, and molecular sensing. They offer numerous functionalities and are hence superior to paper-based devices for point-of-care biochips, with only slightly more investment in fabrication and material costs required. In this review, we first discuss the fundamentals of several nonequilibrium ion current phenomena associated with ion-selective membranes, many of them revealed by studies with fabricated single nanochannels/nanopores. We then focus on how the plethora of phenomena has been applied for transport, separation, concentration, and detection of biomolecules on biochips.
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Affiliation(s)
- Zdenek Slouka
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556; , ,
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